Secure Computation System for Efficient Power-of-2 Calculation
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Solution Overview
Problem
Existing secure computation methods for calculating a power of 2 require lengthy calculations, particularly when dealing with decimal fraction portions, leading to increased computation time.
Innovation Solution
A secure computation system that decomposes an input value into integer and decimal fractions, reconstructs the decimal fraction, performs a left shift operation, and multiplies by a power of 2, allowing for the calculation of 2 raised to a given power without computing a polynomial.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If calculation of a fourth-order polynomial in f is performed to calculate 2f, then the calculation is completed, but the calculation time becomes undesirably long
Solution Approach 1:
The exponent x is segmented into an integer portion e and a decimal fraction portion f (x = e + f). This segmentation allows the calculation of 2x to be divided into calculating 2e (which is efficient) and 2f (which requires the polynomial). By separating the exponent, the patent reduces the frequency of polynomial calculations needed.
Solution Approach 2:
The patent pre-calculates and stores values of 2f for various decimal fraction portions f in a lookup table. When calculating 2x, instead of performing polynomial calculation every time, the system retrieves the pre-computed 2f value from the table, significantly reducing calculation time while maintaining accuracy.
2Reliability
If secure computation is performed by distributing information over multiple devices, then security is improved, but the complexity of the computation system increases
Solution Approach 1:
The patent segments the computation task across multiple secure computation devices, with each device holding shares of the input values. The exponent x is split into portions that are distributed among devices, and each device performs simplified calculations on its local shares rather than handling the complete polynomial calculation, reducing individual device complexity while maintaining overall security.
Solution Approach 2:
The patent introduces an intermediary mechanism where a lookup table is shared among the secure computation devices. Instead of each device independently performing complex polynomial calculations, they collaborate to retrieve pre-computed values from the shared table, simplifying the computation each device must perform while maintaining security through distributed access.
Data Source
AI summary
A secure computation system calculates concealed text of a difference x−r from concealed text by using concealed text and generates concealed text and of an integer portion e and a decimal fraction portion f (0≤f<1) of the difference x−r from the concealed text; reconstructs the decimal fraction portion f from the concealed text; generates, from the decimal fraction portion f and the concealed text, concealed text of a left shift value y obtained by shifting 2f, which is 2 raised to the power f which is the decimal fraction portion f, to the left by e bit; and calculates, as concealed text, concealed text of a value 2r×y obtained by multiplying 2r, which is a power of 2, by the left shift value y from the concealed text by using the concealed text.